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This commit improves how GDB handles file backed mappings within a core file, specifically, this is a restructuring of the function core_target::build_file_mapping. The primary motivation for this commit was to put in place the infrastructure to support the next commit in this series, but this commit does itself make some improvements. Currently in core_target::build_file_mapping we use gdbarch_read_core_file_mappings to iterate over the mapped regions within a core file. For each region a callback is invoked which is passed details of the mapping; the file the mapping is from, the offset into the file, and the address range at which the mapping exists. We are also passed the build-id for the mapped file in some cases. We are only told the build-id for the mapped region which actually contains the ELF header of the mapped file. Other regions of the same mapped ELF will not have the build-id passed to the callback. Within core_target::build_file_mapping, in the per-region callback, we try to find the mapped file based on its filename. If the file can't be found, and if we have a build-id then we'll ask debuginfod to download the file. However we find the file, we cache the opened bfd object, which is good. Subsequent mappings from the same file will not have a build-id set, but by that point we already have a cached open bfd object, so the lack of build-id is irrelevant. The problem with the above is that if we find a matching file based on the filename, then we accept that file, even if we have a build-id, and the build-id doesn't match. Currently, the mapped region processing is done in a single pass, we call gdbarch_read_core_file_mappings, and for each mapping, as we see it, we create the data structures needed to represent that mapping. In this commit, I will change this to a two phase process. In the first phase the mappings are grouped together based on the name of the mapped file. At the end of phase one we have a 'struct mapped_file', a new struct, for each mapped file. This struct associates an optional build-id with a list of mapped regions. In the second phase we try to find the file using its filename. If the file is found, and the 'struct mapped_file' has a build-id, then we'll compare the build-id with the file we found. This allows us to reject on-disk files which have changed since the core file was created. If no suitable file was found (either no file found, or a build-id mismatch) then we can use debuginfod to potentially download a suitable file. NOTE: In the future we could potentially add additional sanity checks here, for example, if a data-file is mapped, and has no build-id, we can estimate a minimum file size based on the expected mappings. If the file we find is not big enough then we can reject the on-disk file. But I don't know how useful this would actually be, so I've not done that for now. Having found (or not) a suitable file then we can create the data structures for each mapped region just as we did before. The new functionality here is the extra build-id check, and the possibility of rejecting an on-disk file if the build-id doesn't match. This change could have been done within the existing single phase approach I think, however, in the next approach I need to have all the mapped regions associated with the expected build-id, and the new two phase structure allows me to do that, this is the reason for such an extensive rewrite in this commit. There's a new test that exercises GDB's ability to find mapped files via the build-id, and this downloading from debuginfod. |
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| bfd | ||
| binutils | ||
| config | ||
| contrib | ||
| cpu | ||
| elfcpp | ||
| etc | ||
| gas | ||
| gdb | ||
| gdbserver | ||
| gdbsupport | ||
| gnulib | ||
| gold | ||
| gprof | ||
| gprofng | ||
| include | ||
| ld | ||
| libbacktrace | ||
| libctf | ||
| libdecnumber | ||
| libiberty | ||
| libsframe | ||
| opcodes | ||
| readline | ||
| sim | ||
| texinfo | ||
| zlib | ||
| .cvsignore | ||
| .editorconfig | ||
| .gitattributes | ||
| .gitignore | ||
| .pre-commit-config.yaml | ||
| ar-lib | ||
| ChangeLog | ||
| compile | ||
| config-ml.in | ||
| config.guess | ||
| config.rpath | ||
| config.sub | ||
| configure | ||
| configure.ac | ||
| COPYING | ||
| COPYING3 | ||
| COPYING3.LIB | ||
| COPYING.LIB | ||
| COPYING.LIBGLOSS | ||
| COPYING.NEWLIB | ||
| depcomp | ||
| djunpack.bat | ||
| install-sh | ||
| libtool.m4 | ||
| lt~obsolete.m4 | ||
| ltgcc.m4 | ||
| ltmain.sh | ||
| ltoptions.m4 | ||
| ltsugar.m4 | ||
| ltversion.m4 | ||
| MAINTAINERS | ||
| Makefile.def | ||
| Makefile.in | ||
| Makefile.tpl | ||
| makefile.vms | ||
| missing | ||
| mkdep | ||
| mkinstalldirs | ||
| move-if-change | ||
| multilib.am | ||
| README | ||
| README-maintainer-mode | ||
| SECURITY.txt | ||
| setup.com | ||
| src-release.sh | ||
| symlink-tree | ||
| test-driver | ||
| ylwrap | ||
README for GNU development tools This directory contains various GNU compilers, assemblers, linkers, debuggers, etc., plus their support routines, definitions, and documentation. If you are receiving this as part of a GDB release, see the file gdb/README. If with a binutils release, see binutils/README; if with a libg++ release, see libg++/README, etc. That'll give you info about this package -- supported targets, how to use it, how to report bugs, etc. It is now possible to automatically configure and build a variety of tools with one command. To build all of the tools contained herein, run the ``configure'' script here, e.g.: ./configure make To install them (by default in /usr/local/bin, /usr/local/lib, etc), then do: make install (If the configure script can't determine your type of computer, give it the name as an argument, for instance ``./configure sun4''. You can use the script ``config.sub'' to test whether a name is recognized; if it is, config.sub translates it to a triplet specifying CPU, vendor, and OS.) If you have more than one compiler on your system, it is often best to explicitly set CC in the environment before running configure, and to also set CC when running make. For example (assuming sh/bash/ksh): CC=gcc ./configure make A similar example using csh: setenv CC gcc ./configure make Much of the code and documentation enclosed is copyright by the Free Software Foundation, Inc. See the file COPYING or COPYING.LIB in the various directories, for a description of the GNU General Public License terms under which you can copy the files. REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info on where and how to report problems.